As radial anti-friction bearings that can also be loaded with high axial forces, in practice, primarily single-row deep groove ball bearings are used, because these feature a uniform high radial and axial load capacity, low friction, and the highest rotational speed limits of all bearing types. These deep groove ball bearings are made, in a known way, from an outer bearing ring and an inner bearing ring, and also from a number of bearing balls arranged between the bearing rings as anti-friction bodies. Here, in the inside of the outer bearing ring and in the outside of the inner bearing ring, groove-shaped raceways are incorporated that are each limited by two axial rims and in which the bearing balls are guided spaced apart at uniform distances relative to each other by a bearing cage. The use of the bearing balls in the deep groove ball bearing is here usually realized by the eccentric mounting method that has become known with DE 168 499 in which the two bearing rings are arranged eccentric to each other and the resulting free space between the bearing rings is filled with the bearing balls. Then the inner bearing ring is brought into a position concentric to the outer bearing ring under use of the elasticity of both bearing rings, so that the bearing balls can then be distributed uniformly in the raceways of the bearing rings and the bearing cage can be used.
In practice, however, it has been proven that such deep groove ball bearings are nevertheless subject to limits primarily with respect to the radial load capacity of the bearing due to the small maximum number of balls that can be installed. This number is dependent on the dimensions of the inner and the outer bearing rings and also the ball diameter. Therefore, in the past a plurality of solutions, such as, for example, an unsealed filling opening according to DE 151 483 arranged in opposite rims of the raceways of the outer and the inner bearing rings or a similarly constructed closable filling opening according to DE 24 07 477 A1, has been proposed with which an increase of the radial load capacity by deep groove ball bearings should be achieved by increasing the number of balls. These proposals, however, cannot be realized in practice due to numerous disadvantages.
In addition, another possibility for increasing the number of anti-friction bodies in a radial anti-friction bearing has become known first through DE 311 317 and was improved by DE 43 34 195 A1. For these radial anti-friction bearings formed as single-row deep groove ball bearings, however, the anti-friction bodies are formed not by balls but instead by so-called spherical rollers that are formed with two side surfaces flattened symmetrically from a spherical base shape and also side surfaces arranged parallel to each other. The width of these spherical rollers between their side surfaces is here less than the distance between the radially opposing axial rims of the raceways in the bearing rings, so that filling the bearing with spherical rollers can be performed with the so-called axial mounting method in which the spherical rollers can be inserted in the axial direction into the bearing through the space between the inner ring and the outer ring. If the center point of the bearing rollers is then located at the height of the raceway axis, the spherical rollers are turned once vertically and once horizontally by 90°, so that they can roll with their running surfaces in the raceways of the bearing rings.
However, despite the possibility of inserting these specially shaped spherical rollers axially into the bearing and thus filling the radial anti-friction bearings almost completely with a high number of anti-friction bodies that can be used for high radial loads, such a spherical roller bearing represents only a compromise with respect to the axial load capacity of the bearing. This is based on the fact that the spherical rollers can have a construction that is only relatively flat due to their ability to be inserted in the axial direction into the bearing only with a small width between their side surfaces and the raceways of the spherical rollers in the bearing rings, in order to be able to allow the rotation of the anti-friction bodies into their operating position, without producing too much radial play in the entire bearing. The relatively flat raceways of the spherical rollers, however, cause a relatively small clearance space for axial tilting of the spherical rollers within their raceways, so that primarily the axial load capacity of such a spherical roller bearing is comparatively low and such spherical roller bearings are thus unsuitable for variable axial loads under high operating pressure angles.